Unnamed

if (empty($_POST['username']))
                     {
                                $u=FALSE;
                                $message .= '<p> You forgot to enter your Username!</p>';

                        	}
                        	else
                        	{
										$query = "SELECT username from users WHERE username = $_POST[username]";
										$result = mysql_query($query);
										$num_rows = mysql_num_rows($result); 
							
								if ($num_rows >= 1)
								{
									$u=FALSE;
									$message .= '<p> This username is already in use.</p>';
								}
								else
								{
                                $u = $_POST['username'];
								}
                    }